1/* SPDX-License-Identifier: GPL-2.0 */
2/*
3 * Generic RTC interface.
4 * This version contains the part of the user interface to the Real Time Clock
5 * service. It is used with both the legacy mc146818 and also EFI
6 * Struct rtc_time and first 12 ioctl by Paul Gortmaker, 1996 - separated out
7 * from <linux/mc146818rtc.h> to this file for 2.4 kernels.
8 *
9 * Copyright (C) 1999 Hewlett-Packard Co.
10 * Copyright (C) 1999 Stephane Eranian <eranian@hpl.hp.com>
11 */
12#ifndef _LINUX_RTC_H_
13#define _LINUX_RTC_H_
14
15
16#include <linux/types.h>
17#include <linux/interrupt.h>
18#include <linux/nvmem-provider.h>
19#include <uapi/linux/rtc.h>
20
21extern int rtc_month_days(unsigned int month, unsigned int year);
22extern int rtc_year_days(unsigned int day, unsigned int month, unsigned int year);
23extern int rtc_valid_tm(struct rtc_time *tm);
24extern time64_t rtc_tm_to_time64(struct rtc_time *tm);
25extern void rtc_time64_to_tm(time64_t time, struct rtc_time *tm);
26ktime_t rtc_tm_to_ktime(struct rtc_time tm);
27struct rtc_time rtc_ktime_to_tm(ktime_t kt);
28
29/*
30 * rtc_tm_sub - Return the difference in seconds.
31 */
32static inline time64_t rtc_tm_sub(struct rtc_time *lhs, struct rtc_time *rhs)
33{
34 return rtc_tm_to_time64(lhs) - rtc_tm_to_time64(rhs);
35}
36
37static inline void rtc_time_to_tm(unsigned long time, struct rtc_time *tm)
38{
39 rtc_time64_to_tm(time, tm);
40}
41
42static inline int rtc_tm_to_time(struct rtc_time *tm, unsigned long *time)
43{
44 *time = rtc_tm_to_time64(tm);
45
46 return 0;
47}
48
49#include <linux/device.h>
50#include <linux/seq_file.h>
51#include <linux/cdev.h>
52#include <linux/poll.h>
53#include <linux/mutex.h>
54#include <linux/timerqueue.h>
55#include <linux/workqueue.h>
56
57extern struct class *rtc_class;
58
59/*
60 * For these RTC methods the device parameter is the physical device
61 * on whatever bus holds the hardware (I2C, Platform, SPI, etc), which
62 * was passed to rtc_device_register(). Its driver_data normally holds
63 * device state, including the rtc_device pointer for the RTC.
64 *
65 * Most of these methods are called with rtc_device.ops_lock held,
66 * through the rtc_*(struct rtc_device *, ...) calls.
67 *
68 * The (current) exceptions are mostly filesystem hooks:
69 * - the proc() hook for procfs
70 * - non-ioctl() chardev hooks: open(), release()
71 *
72 * REVISIT those periodic irq calls *do* have ops_lock when they're
73 * issued through ioctl() ...
74 */
75struct rtc_class_ops {
76 int (*ioctl)(struct device *, unsigned int, unsigned long);
77 int (*read_time)(struct device *, struct rtc_time *);
78 int (*set_time)(struct device *, struct rtc_time *);
79 int (*read_alarm)(struct device *, struct rtc_wkalrm *);
80 int (*set_alarm)(struct device *, struct rtc_wkalrm *);
81 int (*proc)(struct device *, struct seq_file *);
82 int (*set_mmss64)(struct device *, time64_t secs);
83 int (*set_mmss)(struct device *, unsigned long secs);
84 int (*alarm_irq_enable)(struct device *, unsigned int enabled);
85 int (*read_offset)(struct device *, long *offset);
86 int (*set_offset)(struct device *, long offset);
87};
88
89struct rtc_device;
90
91struct rtc_timer {
92 struct timerqueue_node node;
93 ktime_t period;
94 void (*func)(struct rtc_device *rtc);
95 struct rtc_device *rtc;
96 int enabled;
97};
98
99/* flags */
100#define RTC_DEV_BUSY 0
101
102struct rtc_device {
103 struct device dev;
104 struct module *owner;
105
106 int id;
107
108 const struct rtc_class_ops *ops;
109 struct mutex ops_lock;
110
111 struct cdev char_dev;
112 unsigned long flags;
113
114 unsigned long irq_data;
115 spinlock_t irq_lock;
116 wait_queue_head_t irq_queue;
117 struct fasync_struct *async_queue;
118
119 int irq_freq;
120 int max_user_freq;
121
122 struct timerqueue_head timerqueue;
123 struct rtc_timer aie_timer;
124 struct rtc_timer uie_rtctimer;
125 struct hrtimer pie_timer; /* sub second exp, so needs hrtimer */
126 int pie_enabled;
127 struct work_struct irqwork;
128 /* Some hardware can't support UIE mode */
129 int uie_unsupported;
130
131 /* Number of nsec it takes to set the RTC clock. This influences when
132 * the set ops are called. An offset:
133 * - of 0.5 s will call RTC set for wall clock time 10.0 s at 9.5 s
134 * - of 1.5 s will call RTC set for wall clock time 10.0 s at 8.5 s
135 * - of -0.5 s will call RTC set for wall clock time 10.0 s at 10.5 s
136 */
137 long set_offset_nsec;
138
139 bool registered;
140
141 /* Old ABI support */
142 bool nvram_old_abi;
143 struct bin_attribute *nvram;
144
145 time64_t range_min;
146 timeu64_t range_max;
147 time64_t start_secs;
148 time64_t offset_secs;
149 bool set_start_time;
150
151#ifdef CONFIG_RTC_INTF_DEV_UIE_EMUL
152 struct work_struct uie_task;
153 struct timer_list uie_timer;
154 /* Those fields are protected by rtc->irq_lock */
155 unsigned int oldsecs;
156 unsigned int uie_irq_active:1;
157 unsigned int stop_uie_polling:1;
158 unsigned int uie_task_active:1;
159 unsigned int uie_timer_active:1;
160#endif
161};
162#define to_rtc_device(d) container_of(d, struct rtc_device, dev)
163
164/* useful timestamps */
165#define RTC_TIMESTAMP_BEGIN_1900 -2208989361LL /* 1900-01-01 00:00:00 */
166#define RTC_TIMESTAMP_BEGIN_2000 946684800LL /* 2000-01-01 00:00:00 */
167#define RTC_TIMESTAMP_END_2099 4102444799LL /* 2099-12-31 23:59:59 */
168
169extern struct rtc_device *devm_rtc_device_register(struct device *dev,
170 const char *name,
171 const struct rtc_class_ops *ops,
172 struct module *owner);
173struct rtc_device *devm_rtc_allocate_device(struct device *dev);
174int __rtc_register_device(struct module *owner, struct rtc_device *rtc);
175
176extern int rtc_read_time(struct rtc_device *rtc, struct rtc_time *tm);
177extern int rtc_set_time(struct rtc_device *rtc, struct rtc_time *tm);
178extern int rtc_set_ntp_time(struct timespec64 now, unsigned long *target_nsec);
179int __rtc_read_alarm(struct rtc_device *rtc, struct rtc_wkalrm *alarm);
180extern int rtc_read_alarm(struct rtc_device *rtc,
181 struct rtc_wkalrm *alrm);
182extern int rtc_set_alarm(struct rtc_device *rtc,
183 struct rtc_wkalrm *alrm);
184extern int rtc_initialize_alarm(struct rtc_device *rtc,
185 struct rtc_wkalrm *alrm);
186extern void rtc_update_irq(struct rtc_device *rtc,
187 unsigned long num, unsigned long events);
188
189extern struct rtc_device *rtc_class_open(const char *name);
190extern void rtc_class_close(struct rtc_device *rtc);
191
192extern int rtc_irq_set_state(struct rtc_device *rtc, int enabled);
193extern int rtc_irq_set_freq(struct rtc_device *rtc, int freq);
194extern int rtc_update_irq_enable(struct rtc_device *rtc, unsigned int enabled);
195extern int rtc_alarm_irq_enable(struct rtc_device *rtc, unsigned int enabled);
196extern int rtc_dev_update_irq_enable_emul(struct rtc_device *rtc,
197 unsigned int enabled);
198
199void rtc_handle_legacy_irq(struct rtc_device *rtc, int num, int mode);
200void rtc_aie_update_irq(struct rtc_device *rtc);
201void rtc_uie_update_irq(struct rtc_device *rtc);
202enum hrtimer_restart rtc_pie_update_irq(struct hrtimer *timer);
203
204void rtc_timer_init(struct rtc_timer *timer, void (*f)(struct rtc_device *r),
205 struct rtc_device *rtc);
206int rtc_timer_start(struct rtc_device *rtc, struct rtc_timer *timer,
207 ktime_t expires, ktime_t period);
208void rtc_timer_cancel(struct rtc_device *rtc, struct rtc_timer *timer);
209int rtc_read_offset(struct rtc_device *rtc, long *offset);
210int rtc_set_offset(struct rtc_device *rtc, long offset);
211void rtc_timer_do_work(struct work_struct *work);
212
213static inline bool is_leap_year(unsigned int year)
214{
215 return (!(year % 4) && (year % 100)) || !(year % 400);
216}
217
218/* Determine if we can call to driver to set the time. Drivers can only be
219 * called to set a second aligned time value, and the field set_offset_nsec
220 * specifies how far away from the second aligned time to call the driver.
221 *
222 * This also computes 'to_set' which is the time we are trying to set, and has
223 * a zero in tv_nsecs, such that:
224 * to_set - set_delay_nsec == now +/- FUZZ
225 *
226 */
227static inline bool rtc_tv_nsec_ok(s64 set_offset_nsec,
228 struct timespec64 *to_set,
229 const struct timespec64 *now)
230{
231 /* Allowed error in tv_nsec, arbitarily set to 5 jiffies in ns. */
232 const unsigned long TIME_SET_NSEC_FUZZ = TICK_NSEC * 5;
233 struct timespec64 delay = {.tv_sec = 0,
234 .tv_nsec = set_offset_nsec};
235
236 *to_set = timespec64_add(*now, delay);
237
238 if (to_set->tv_nsec < TIME_SET_NSEC_FUZZ) {
239 to_set->tv_nsec = 0;
240 return true;
241 }
242
243 if (to_set->tv_nsec > NSEC_PER_SEC - TIME_SET_NSEC_FUZZ) {
244 to_set->tv_sec++;
245 to_set->tv_nsec = 0;
246 return true;
247 }
248 return false;
249}
250
251#define rtc_register_device(device) \
252 __rtc_register_device(THIS_MODULE, device)
253
254#ifdef CONFIG_RTC_HCTOSYS_DEVICE
255extern int rtc_hctosys_ret;
256#else
257#define rtc_hctosys_ret -ENODEV
258#endif
259
260#ifdef CONFIG_RTC_NVMEM
261int rtc_nvmem_register(struct rtc_device *rtc,
262 struct nvmem_config *nvmem_config);
263void rtc_nvmem_unregister(struct rtc_device *rtc);
264#else
265static inline int rtc_nvmem_register(struct rtc_device *rtc,
266 struct nvmem_config *nvmem_config)
267{
268 return 0;
269}
270static inline void rtc_nvmem_unregister(struct rtc_device *rtc) {}
271#endif
272
273#ifdef CONFIG_RTC_INTF_SYSFS
274int rtc_add_group(struct rtc_device *rtc, const struct attribute_group *grp);
275int rtc_add_groups(struct rtc_device *rtc, const struct attribute_group **grps);
276#else
277static inline
278int rtc_add_group(struct rtc_device *rtc, const struct attribute_group *grp)
279{
280 return 0;
281}
282
283static inline
284int rtc_add_groups(struct rtc_device *rtc, const struct attribute_group **grps)
285{
286 return 0;
287}
288#endif
289#endif /* _LINUX_RTC_H_ */
290